3100 vs 3400 head measurements

[SappySE107]

I found a text file from when I had measured a set of 94 3100 heads and the 96 3400 heads. All measurements were taken in the same place, so the port widths are valid as an equal comparison. The valve seat width should be of more interest to some than the recent valve head diameter since that is the real flow improvement. Anyway, posted in case I lose this info again in a sea of unorganized multiple computer file misplacement

3100 head 10154743
Intake height 1.617
Intake width 1.02
Exhaust Height 1.247
Exhaust Width 1.213
Intake valve seat 1.480
Exhaust valve seat 1.177

3400 head 10218170
Intake height 1.70
Intake width 1.033
Exhaust Height 1.244
Exhaust Width 1.217
Intake valve seat 1.574
Exhaust valve seat 1.170

[StudlyCamaro]

thoes differences could have been measurement error or casting flaws couldnt they?

besides the intake valve seat they all look pretty much the same

were both sets of heads measured at the same time in the same place? also were they both hot tanked before measured?

[SappySE107]

both measured at the same time with the same dial caliper. Both heads were cleaned with cleaner. hot tanking is for iron heads isn't it?

measured in the same part, and yes, it can be casting flaws.

[StudlyCamaro]

thats my guess... thoes measurements seem too close to be intentionally different besides the intake valve

you can have alumnium heads hot tanked , it just has to be a hot tank solution for alumnium parts (i had my 3100 heads tanked) , but yeah if they put an alumnium head in an iron hot tank it will eat the head

[SappySE107]

The intake height is deliberate, or at least it has happened on more than just my occasion. The valve seat diameter cant be a casting flaw either, but the rest are too close to be anything else.

[xxrollin]

You used a dial caliper to measure all this. You should send me a 3400 head since I have 3100 heads from a 1995 and 2001. I have access to a Brown N Sharp CMM and can measure everything and get a print out. I never thought of it but could be a way to check why the gaskets dont line up on one intake port. I'm also working with my CAD/CAM to do a port match cause all we have is 4 axis machines and the ports are inclined at to many angles for me to crunch those numbers. Really a 3 axis machine with a HAAZ 4th axis to turn the head around. I got the basic program, just waiting on a custom ground tool to do the work.

[SappySE107]

I dont have any stock 3400 heads anymore.

[xxrollin]

Well from what I've herd, only herd it from this site and one other, that the 2001 3100 heads are the exact same as the "say 3400 from 99 and up". So I'm assuming here that if they are the same, I can have them checked out. I know a few people that have experienced the intake manifold gasket not lining up properly with one port. I had that same problem with every 3100 I've seen so far and I even tried the 3400 gaskets and the same problem. So I'll investigate and see what I come up with today or monday when I have some free time at work. I'll check the intake port centerlines vs the intake manifold port centerlines and see if there square with eachother..

[xxrollin]

Ok, as an update on getting these checked out, I didnt get everything done 100%. I was able to get the port centerlines done and I had the problem when I ran them against the LIM numbers. I think that because the heads ports are not straight that its throwing off the numbers. But I also used the threaded hole in the head as my tooling hole and used the thru hole on the manifold as my tooling hole, so its not the most accurate since I had to stick a pin in the threaded hole in the head to get better numbers. But hey, I tried and I dont have a 3400 head to check to the 3100 head to either. Also, anyone know the formula to check the intake port CC's. It'd be interesting to see how big/small they are.

[Corpse]

"Also, anyone know the formula to check the intake port CC's" - It's just a matter of calculating volume.

It's just that the ports are oddly shaped and you'd never really be able to do math and get it correct.

I would assume that using water that is at a certain temperature, and also the head at the same temperature would give you a closer rough idea than trying from a bunch of measurements. Just make sure there are no air pockets.

-Dave

[bszopi]

~28cc

[xxrollin]

Yeah, but I can crunch numbers. I know its something like length by width and some trig involved. I'm talking about the port CC bszopi. I know the chamber is 28cc's. I'll have to call AFR or someone that might know the formula, then I'll post it.